Mixing tools for drying, mixing, and coating.

Abstract

The present invention relates to a tool for drying, mixing, and coating a mixed powder. [Solution] The present invention relates to a tool (1) for drying, mixing, and coating a powder mixture, comprising a fixed shaft (2) and a disc-shaped element (4) fixed thereto, having a diameter d, an upper surface, a lower surface, and an outer peripheral surface connecting the upper and lower surfaces, wherein the disc-shaped element has a number of grooves extending parallel to the shaft axis, each groove having two groove walls extending from the outer peripheral surface to the groove bottom, and teeth formed between the two groove walls. In particular, in order to provide a tool suitable for drying, mixing, drying, and coating a powder mixture with minimal contamination, the present invention proposes that the disc-shaped element has a base portion and at least one wear element (6) fixed to the base portion, and that at least one portion of each groove wall adjacent to the outer peripheral surface is formed by the wear element.

Description

Technical Field

[0001] The present invention relates to a tool for dry-mixing and coating a mixed powder. In the dry-mixing process, a large number of dry materials, generally in powder form, are mixed with each other. In the coating process, coarse powder particles are enveloped by dry-mixing while fine particles are deposited on the surface of the coarse particles. Instead of, or in combination with, the fine particles, a liquid is applied in a minute amount to the coarse powder to wet the particle surface as completely as possible.

Background Art

[0002] Patent Document 1 discloses a rotary tool for a powerful mixer for finely granulating a wet solid mixture. The rotary tool has a fixed shaft and a disk-shaped element fixed to the fixed shaft, the disk-shaped element having a diameter d, an upper surface, a lower surface, and an outer peripheral surface connecting the upper surface and the lower surface. The outer peripheral surface has a number of grooves extending parallel to the shaft axis. Each groove has two groove walls extending from the outer peripheral surface to the groove bottom, and teeth are formed between each two adjacent grooves.

[0003] The concept of the outer peripheral surface is interpreted such that the groove walls and the groove bottom are not part of the outer peripheral surface. Thus, the outer peripheral surface is interrupted by the formed grooves. When the disk-shaped element is exactly circular, the outer peripheral surface is located on the circumcircle of the disk-shaped element.

[0004] In this known rotary tool, the rotation direction of the tool is defined. Therefore, the groove walls following the rotation direction are provided with hard metal (carbide) elements to reduce the wear of the tool, especially at the radially outer ends.

[0005] When finely granulating a wet solid mixture, the wear of the tool is undesirable because it leads to deterioration of the result, but wear is inevitable with groove walls without hard metal. This small debris falls into the mixture and is inevitably mixed into the product, which is not a problem in normal application situations.

[0006] Therefore, known tools are, in principle, unsuitable for the dry mixing and coating of powder mixtures, especially when attempting to do so with as little iron as possible. This is because, structurally, it is impossible to prevent fragments of the iron-formed tool from reaching the mixture, which must be unconditionally avoided in the case of contamination-free dry mixing. That is, any contamination of the mixture, for example, by tool wear, must be avoided when forming cathode materials for energy storage devices. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2012 / 123441(A1) [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Therefore, the object of the present invention is to provide a tool suitable for dry mixing, dry dispersing, and coating of powder mixtures, particularly with minimal contamination. [Means for solving the problem]

[0009] According to the present invention, the disc-shaped element has a base portion and at least one wear element fixed to the base portion, and the problem is solved by forming at least one portion of each groove wall adjacent to the outer circumferential surface with at least one wear element.

[0010] Therefore, according to the present invention, not only the groove walls oriented in the rotational direction, but also the opposing groove walls and, in the best case, the outer circumferential surface at the radially outer end of the tooth are covered by the wear element. Experiments have shown that wear occurs mainly in the portion of the groove wall that is continuous with the outer circumferential surface.

[0011] By using abrasion elements on both groove walls, wear or abrasion can be significantly reduced, and less contaminated operation is possible.

[0012] In principle, it is possible for all teeth, or especially a group of teeth, to be formed as wear elements. It is also possible to provide each tooth with a wear-protective cap to enclose it.

[0013] In all these cases, the portion of each groove wall adjacent to the outer circumferential surface is formed by at least one wear element. Therefore, multiple wear elements can be provided within a single groove, forming at least portions of opposing groove walls, or they can form wear elements as an entire tooth group or even individual teeth. However, in each case, it is guaranteed that at least one portion of each groove wall adjacent to the circumferential surface is made of a wear-resistant material. A wear-resistant material is a material having increased wear resistance compared to the base body material.

[0014] Embodiments of the present invention further have the advantage that the rotational direction of the tool can be changed while it is still in operation, thereby achieving operation that minimizes dust generation.

[0015] Preferably, the wear element is made of a hard metal. However, other wear-resistant non-ferrous materials, such as ceramics, can also be used effectively.

[0016] In other preferred embodiments, the two groove walls and preferably the groove bottom are also formed by at least one abrasion element. In other words, not only the portions of the groove walls adjacent to the outer circumferential surface, but all groove walls and preferably the groove bottom have or are formed by abrasion elements. Furthermore, the outer circumferential surface between the two grooves may also have or be formed by abrasion elements. This can further reduce wear.

[0017] In a preferred embodiment, the wear element is composed of multiple parts.

[0018] It has been shown that the groove bottom has a groove bottom length extending from the first groove wall to the second groove wall, and that this is at least 10%, preferably at least 25%, of the groove wall length extending from the groove bottom to the outer surface.

[0019] Furthermore, at least 20%, preferably at least 50%, of the groove wall length is formed by at least one abrasion element.

[0020] The V-shaped groove shown in Patent Document 1 cited above has the disadvantage that, during dry mixing, in some cases, especially with sticky raw materials, the mixture components accumulate near the bottom of the groove and no longer participate in the mixing process. By forming the bottom of the groove as described above, the groove is made much larger, especially within the area of ​​the bottom of the groove, so the risk of the mixture components adhering to the bottom of the groove is significantly reduced.

[0021] To ensure efficient mixing, the grooves should not be formed too small.

[0022] In another preferred embodiment, the groove wall has a groove wall length extending from the outer circumferential surface to the groove bottom, the groove wall length being between 0.05 and 0.4 times the diameter d of the disk-shaped element, preferably between 0.1 and 0.3 times, and most preferably between 0.15 and 0.25 times.

[0023] In another preferred embodiment, the lower surface has at least one vortex-inducing element that protrudes beyond the lower surface, preferably a plurality of vortex-inducing elements, which are preferably spaced at the same angular interval in the circumferential direction.

[0024] Due to the vortex-inducing element, the material reaching below the disk is pushed outward and upward, so that the material in the groove can flow upward. Thus, it is prevented that the mixture components fall to the bottom of the container where the tool is used inside and no longer participate in the mixing process. The vortex-inducing element is preferably made of a wear-resistant material such as, for example, hard metal or ceramic. The vortex-inducing element can also be made of a hardened metal such as, for example, hardened steel.

[0025] It is shown that in order to effect efficient mixing, at least four vortex-inducing elements are provided. In the most preferred case, more than ten vortex-inducing elements are provided.

[0026] In another preferred embodiment, at least one vortex-inducing element can reciprocate between two positions, and the vortex-inducing element protrudes less beyond the lower surface at the first position than at the second position.

[0027] The vortex-inducing element can be fixed at the second position, whereby the vortex-inducing element does not move unintentionally between the first position and the second position during the driving of the tool. For example, the vortex-inducing element is adjustable in length, and the movement between the first position and the second position is performed by adjusting the length.

[0028] Alternatively, the length by which the vortex-inducing element axially protrudes beyond the lower surface of the disk-shaped element can be varied by the vortex-inducing element screwed to the disk-shaped element and one or more support shims arranged between the vortex-inducing element and the disk-shaped element.

[0029] This measure makes it possible to position the eddy-inducing elements as close as possible to the surface of the container in which the tool is placed. Typically, this is desirable when at least one, preferably two, eddy-inducing elements are positioned as close together as possible to the bottom of the container to prevent adhesion. Preferably, the distance between the lower edge of the eddy-inducing elements and the upper edge of the bottom of the container is between a few tens of millimeters and several millimeters, and especially in the best case, between 0.2 mm and 5 mm. The remaining eddy-inducing elements can have a greater distance from the surface of the bottom of the container.

[0030] However, it may be necessary to move the entire tool axially toward the bottom in order to separate the tool from the appropriate drive device or flange having centering. This too can be made possible by the measures according to the present invention, because in that case the eddy current inducing element can be moved from the second position to the first position, thereby leaving a larger gap between the eddy current inducing element and the bottom of the container, and allowing the entire tool to be moved axially to separate it from the drive device.

[0031] This can also be achieved by fixing the eddy current inducing element by having a threaded hole in the eddy current inducing element, into which a screw is inserted through a through-hole in the disc-shaped element. When attempting to move the tool axially toward the bottom of the container, the eddy current inducing element that protrudes further axially must be detached from the disc-shaped element and removed radially.

[0032] In a preferred embodiment, the eddy current inducing element is also formed from a wear element. For example, the wear element may consist of a group of teeth and an integrally formed, for example, welded, eddy current inducing element.

[0033] It has been shown that the vortex-inducing element is positioned as close as possible to the fixed shaft than to the groove bottom, preferably the distance between the fixed shaft and the vortex-inducing element is less than 50%, preferably less than 75%, and in best case between 80 and 98%, of the distance between the groove bottom and the fixed shaft.

[0034] The present invention also relates to an apparatus for drying, mixing, or coating powder mixtures, comprising a container and a tool according to the present invention arranged therein.

[0035] Preferably, the container is rotatable about its axis, the container axis is separated from the fixed shaft axis, and preferably the diameter d of the disc-shaped element is between 30 and 70% of the container diameter.

[0036] In another preferred embodiment, the tool is positioned inside the container such that the minimum distance between the outer surface of the tool and the container wall is less than 10% of the container diameter.

[0037] Other advantages, features, and applicability will be revealed using the following description of preferred embodiments and accompanying drawings. [Brief explanation of the drawing]

[0038] [Figure 1] This is a perspective view showing a first embodiment of the present invention. [Figure 2] This shows a part of the first embodiment of the present invention. [Figure 3] This is a perspective view showing a part of a second embodiment of the present invention. [Figure 4] This is a perspective view showing a third embodiment of the present invention. [Modes for carrying out the invention]

[0039] Figure 1 shows a perspective view of a first embodiment of the present invention.

[0040] The tool 1 according to the present invention has a fixed shaft 2 equipped with a flange 3. The tool 1 can be fixed to a drive device (not shown) via the flange 3 and can rotate about the axis of the fixed shaft 2.

[0041] A disc-shaped element 4 is positioned at the end of tool 1 opposite to the flange 3, and the axis of the disc coincides with the axis of the fixed shaft 2.

[0042] The disc-shaped element has a top surface as shown in Figure 1, a bottom surface not shown in Figure 1, and an outer circumferential surface connecting the top and bottom surfaces. It is recognized that the disc-shaped element has a number of teeth 5, which are formed by grooves extending parallel to the shaft axis. By forming grooves in the disc-shaped element, the teeth 5 remain between the grooves. In the embodiment shown in the figure, the two groove walls are covered by a wear element 6 consisting of . In the illustrated embodiment, two parts of the wear element 6 are attached to each groove wall. The radially outer part of the wear element is positioned on the groove wall, continuous with the outer circumferential surface. All other parts of the wear element on the groove wall are continuous with a wear element part positioned further radially outward, preferably directly toward the groove bottom. In this embodiment, the groove bottom 7 is not covered by a wear element.

[0043] However, to reduce wear, it is entirely possible to cover the entire groove walls and groove bottoms, as well as the outer circumferential surface between two grooves, with one or more wear elements. All other parts of the mixing tool that may come into contact with the mixture, such as the fixed shaft and disc-shaped elements, are protected from wear by applying a wear-resistant layer in a preferred embodiment. This layer can be formed, for example, by surface hardening or using a coating. The coating can consist of a plastic such as polyurethane, or a surface hardening agent. Spray coating is particularly effective, by which ceramic or hard metal is coated. In this case, the thickness of the spray coating layer should be at least 0.1 mm and particularly preferably greater than 0.4 mm. Furthermore, it is effective if the surface roughness of the coating is selected such that a thin layer of particles adheres to a thick layer of the product, thereby protecting the tool from abrasion and consequent wear.

[0044] Vortex-inducing elements 8 and 8' are positioned on the underside of the disk-shaped element, protruding beyond the underside. In the illustrated example, vortex-inducing element 8 is formed to be height-displaceable, i.e., to reciprocate between two positions or to be displaced along its length, so that in the first position, vortex-inducing element 8 protrudes less from the underside than in the second position.

[0045] Figure 2 shows a magnified view of the disk-shaped element having the eddy current inducing element shown in Figure 1. The eddy current inducing element 8 is fixed to the disk-shaped element 4 via a removable screw 12. One or more support shims 11 are installed between the eddy current inducing element 8 and the disk-shaped element 4 to adjust the gap to the bottom of the container as small as possible and to compensate for manufacturing tolerances. If the manufacturing tolerance is very small, the support shims can be omitted entirely.

[0046] Figures 3 and 4 illustrate other embodiments of the present invention. Figure 3 is a perspective view of the tool from above, and Figure 4 shows the tool from below.

[0047] Where possible, the same reference numerals are used for the same components as in Figure 1. The tools in Figures 3 and 4 differ from the embodiment in Figure 1, on the one hand, by the eddy-inducing element 8' which is not height-adjustable in this embodiment, and by the configuration of the wear element 6' portion.

[0048] Figure 3 shows a modified version of the present invention, in which the wear element 6' comprises individual teeth formed entirely from ceramic, for example. The wear element 6' is suspended by shape coupling within a suitable notch in the base plate via projections provided at the ends of the wear element, and cannot move radially. Vertical movement of the wear element within the notch can be prevented, for example, by circular or annular cover plates on the upper and lower sides of the base plate that partially or completely cover the notch. The ends of the wear element facing the projections are teeth 5 having groove walls 9 and 10. The eddy-inducing element 8' can be fixed to the wear element 6' portion.

[0049] In particular, as can be seen in Figure 4, the wear element here consists of numerous wear element 6' portions, each forming one of the seven teeth 5 of the tool. In other words, in this embodiment, not only are the groove bottom 7 and groove walls 9 covered by wear elements made of, for example, hard metal, but the entire tooth, i.e., the entire wear element 6', is formed of, for example, hard metal. In Figure 4, the underside of a substantially disc-shaped element is visible. Furthermore, it is shown that the eddy-inducing element 8' is fixed to the wear element 6' portion. [Explanation of Symbols]

[0050] 1 tool 2 Fixed shaft 3 flanges 4. Disk shape elements 5 teeth 6, 6' wear element 7 Groove bottom 8, 8' Vortex-inducing elements 9. Ditch wall 10 trench wall 11 Support SIM 12 screws

Claims

1. A tool for drying, mixing, and coating a powder mixture, comprising a fixed shaft and a disc-shaped element fixed to the fixed shaft, having a diameter d, an upper surface, a lower surface, and an outer peripheral surface connecting the upper and lower surfaces, In a tool in which a disc-shaped element has numerous grooves extending parallel to the shaft axis, each groove has two groove walls extending from the outer surface to the groove bottom, and teeth are formed between the two groove walls, The disc-shaped element comprises a base portion and at least one wear element fixed to the base portion. A tool characterized in that at least one portion of each groove wall adjacent to the outer circumferential surface is formed by the wear element.

2. The tool according to claim 1, characterized in that the abrasion element is made of a hard metal or other wear-resistant non-ferrous material.

3. The tool according to claim 1 or 2, characterized in that the two groove walls and preferably the groove bottom are formed by the wear element.

4. The tool according to any one of claims 1 to 3, characterized in that the wear element is composed of multiple parts.

5. The tool according to any one of claims 1 to 4, characterized in that the groove bottom has a groove bottom length extending from the first groove wall to the second groove wall, and the groove bottom length is at least 10%, preferably at least 25%, of the groove wall length from the groove bottom to the outer circumferential surface.

6. The tool according to any one of claims 1 to 5, characterized in that the groove wall has a groove wall length extending from the outer peripheral surface to the groove bottom, and the groove wall length is between 0.05 and 0.4 times the diameter d, preferably between 0.1 and 0.3 times, and best between 0.15 and 0.25 times.

7. The tool according to any one of claims 1 to 6, characterized in that the lower surface has at least one vortex inducing element, the vortex inducing element protrudes beyond the lower surface, preferably a plurality of vortex inducing elements are provided, and particularly preferably the plurality of vortex inducing elements are spaced at equal angular intervals in the circumferential direction.

8. The tool according to claim 7, characterized in that at least one vortex-inducing element is reciprocally movable between two positions or can be varied in length, and the vortex-inducing element protrudes less above the lower surface at the first position than at the second position.

9. The tool according to either claim 7 or 8, characterized in that the vortex-inducing element is formed by the wear element.

10. The tool according to any one of claims 7 to 9, characterized in that the vortex-inducing element is positioned closer to the fixed shaft than to the groove bottom, and preferably the distance between the fixed shaft and the vortex-inducing element is less than 50%, preferably less than 75%, and best between 80% and 98% of the distance between the groove bottom and the fixed shaft.

11. An apparatus for drying, mixing, and coating a powder mixture, comprising a container and a tool according to any one of claims 1 to 10, placed inside the container.

12. The apparatus according to claim 11, characterized in that the container is rotatable about a container axis away from the fixed shaft axis, and preferably the diameter d of the disk-shaped element is between 30 and 70% of the container diameter.

13. The apparatus according to claim 11 or 12, characterized in that the tool is placed inside the container and the minimum distance between the outer surface of the tool and the container wall is less than 10% of the container diameter.

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